An infinite wire bent in the form of I carries current i. What is the magnetic field at the point O ?

• A

  zero

• B

  $\frac{{\mathrm{\mu }}_0}{4\mathrm{\pi }}\times \frac{\mathrm{i}}{p}$

• C

  $\frac{{\mathrm{\mu }}_0}{4\mathrm{\pi }}\times \frac{\mathrm{i}}{2p}$

• D

  $\frac{{\mathrm{\mu }}_0\mathrm{i}(1+\sqrt{2})}{4\sqrt{2}\mathrm{\pi p}}$